Aggregate dividends declared during the period for each share of common stock outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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Date the declared dividend will be paid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

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Date the dividend to be paid was declared, in CCYY-MM-DD format.

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Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph d
-URI http://asc.fasb.org/extlink&oid=77990344&loc=d3e5747-111685

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Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions									6 Months Ended
	Aug. 08, 2018	Jul. 06, 2018	May 03, 2018	Feb. 02, 2018	Oct. 31, 2017	Aug. 02, 2017	May 04, 2017	Feb. 09, 2017	Jun. 30, 2018
Subsequent Event [Line Items]
Variable Interest Entity, Measure of Activity, Other, Amount									$ 34.6
Dividends declared date			May 03, 2018	Feb. 02, 2018	Oct. 31, 2017	Aug. 02, 2017	May 04, 2017	Feb. 09, 2017
Dividend amount to be paid, per common share			$ 0.4150	$ 0.4050	$ 0.3950	$ 0.3850	$ 0.3750	$ 0.3650
Date dividend is payable			Jun. 01, 2018	Mar. 09, 2018	Dec. 05, 2017	Sep. 01, 2017	Jun. 02, 2017	Mar. 09, 2017
Date shareholders must be on record for dividend			May 18, 2018	Feb. 22, 2018	Nov. 17, 2017	Aug. 14, 2017	May 19, 2017	Feb. 22, 2017
Subsequent Event [Member]
Subsequent Event [Line Items]
Variable Interest Entity, Measure of Activity, Other, Amount		$ 12.9
Dividends declared date	Aug. 08, 2018
Dividend amount to be paid, per common share	$ 0.4250
Date dividend is payable	Sep. 04, 2018
Date shareholders must be on record for dividend	Aug. 20, 2018